I think from the picture it maybe involved having your arms straight, like at the top of a push-up?

Isn't a normal plank with your elbows on the ground?

I took one look and thought - that is going to completely bugger up my wrists (which are one of my Achilles heels, so to speak) if I try it. Plus, my core's fine as it is - gradually spreading at the base for added stability.

Like I say - I didn't click on it, so the arms straight thing may simply have been a preparatory stage. Or maybe the new plank is just 'push-ups'.